University:
Swansea University
Course:
PM-133 | Evolutionary and Molecular Genetics
Academic year:

2023
Views:

405

Pages:

4
Author:

Amal J.

Regulation of Bacterial ReplicationTo ensure replication occursonly once before aOnacelldivisto(1) RIDA (Regulatory Inactivation of DNA A.)Hda(Homologue of DhaA + Bcloup)Bclamp.decrease the availability of Dna A-ATP.DnaA-ATPDna-ADPDna ATPconc in not enoughto reintiate replication fromOric.(6) SequestrationCH3Eukayotes - Cytosino1OricontainGATCSymmetric methylaticsGAT(palypdorCTAGof A in GATC melhylatedCAY seq, symmetricallymethylated (to'A'CH3GATConlyrecognisesCH32replication non metholated seq.GATCGATC3 sea+CTAGbindCATAGbemiein them methylatedCH3newlymethylated form4DnaA-ATPseacynthesizedDnaA - ATPsemimethylatedsemimethylatedstrand.afterTimetfully methy bab(3) DnaA titrationOric + DnaAATPintiation of replicationImmediately adjacent toonichigh affinity to dnaA-ATP complex.DatA locus8 than time more OricC. affinity to DnaA-ATP)If 100 occupiesOric DatA - 800ofdnaAAT bind23E cytherfor intiation 900AT Pin requiredOric datA100800ReplicationOriC datAOrie data50 40050 400dilution ofOric & dat A site sonlylers dnaAATP'sa variable inthe cell.Replication cannot be intiatedsince 900 dnaA-ATP's didn'tbind to Oric + dat Asites.Calculate the time required to replicate entire Ecotiehromosome4.6x10 6bp.Time varies with availability of nutri entreplication of one strond - 100 Socleotides 2 per secondO.aetrands i. 4.6x106BP = 2.3 x10E13.22000 6038.33= 2306/230618= 38.35 minutes504820 when cell divide DNA is in half way replicatedcondition when nutrients areabundantwhen nutrients are less the cell inbibits reintiatby the above mentioned 3mech onisms.within 20 minutes bacterial cell can divide whonnutrients are abundantIturn105bp ,360°, parbase 360 36°10.536 turnsrotateleft-ve supercoilsright+vesupacoilsright bardedgraftamanycoils DNA seperationbecomes difficult due to accumilationof supercoilswatsonTTwist (priof DNA ina twists794per base36hk=Ttwwrith Csuperit360°linkingvesuparco.numtoLK = 36+C (LkotinkingNumber ofrelaxed4DNA- vesupercollLK linkingnoLK= 36 - 4 sex= 32 coilrelatation of firtsuper coil neutralizerelaxDN1- ve supercoil & relations of 4 thesuper coil -(36-4)+(4-4)LK= 32+0=ItveL K=32+1=33 Daterallyocuring DNA-ve supercoils.osuperbelical density (OMA replicationLK-LKowill stall when C - 0044=32-36LKo36= - 0.11(this indicates -veLKo - Linking no: of relaxed DNAsupercolling).only T W=0364-ve superorT=36, W=4LK - Linking no: of supercoiled DNA.Topoisomeraserevere gyraseI+vvesupercois, ,cleave 1 strond +1 at atimeII-ve vesupercoil, cleave both strond-2 - atativeGatesegnautGyraseClasstopoisomeraseTseggiven800